


Phosphorescence

by kickcows



Category: Big Hero 6 (2014)
Genre: Aged-Up Hiro, Consensual, Dry Humping, Kissing, M/M, Sibling Incest
Language: English
Status: Completed
Published: 2016-12-08
Updated: 2016-12-08
Packaged: 2018-09-07 06:39:04
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,064
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8787556
Author URL: https://archiveofourown.org/users/kickcows/pseuds/kickcows
Summary: Tadashi finds out from Honey Lemon that there’s going to be something cool happening at the beach, and he decides to take Hiro to see it with him.





	

**Author's Note:**

> Written for a dear friend of mine. Please enjoy!

* * *

***

 

“You boys be careful, okay?” Aunt Cass stands on the sidewalk, wearing a concerned look on her face.

Tadashi puts the last item in the back of the pick-up truck. He sees Hiro climbing in the cab, on the passenger’s side. “Don’t worry, Aunt Cass. It’s just for the night. We’ll be back tomorrow evening.” He walks over to her, and plants a kiss on her cheek. “We’ll be safe.”

“I know, I know. I just can’t help but worry when both of my boys leave me.” She grabs him in a tight hug, the wind being knocked out of him. He hears Hiro snickering behind him, and apparently so does his aunt, who stops hugging him to go over to where Hiro is. “Don’t think I’m not going to smother you too, little man.”

He watches HIro groan, as their aunt pushes herself through the open window, and hugs him just as tight. “Aunt Cass, it’s not like we’re going far away! We’ll just be down at the beach!”

“Doesn’t matter if you’re going down the street. I’ll still miss you like crazy!” She lets go of HIro, as Tadashi slides into the driver’s seat. “You boys have fun, but be safe!”

“Yes, Aunt Cass,” the two say together, as Tadashi starts the car.

They wave goodbye to her, with two enthusiastic waves. Hiro rolls up the window, as Tadashi merges into traffic. Tadashi had heard from Honey Lemon that some bioluminescent algae was due to show up on shore late tonight, so he had sent a text to Hiro and said that they were going on an overnight trip. After a few back and forth texts, Hiro had finally - begrudgingly - agreed. Tadashi doesn’t say why they were going to the beach, because he wants to keep it a surprise. He only hopes none of the others in the nerd squad have clued Hiro in.

“Are we watching the grunions?” Hiro asks, as Tadashi pulls onto the highway, heading south. “Because, I gotta tell you, that sounds kinda lame.”

Chuckling, Tadashi keeps his eyes on the road. “I mean, we could be doing that. Or, maybe it’s because it’s going to be a super moon tonight, and the best place to see it is at the state beach, away from all the light pollution.”

“You’re a real nerd. You know that, right, Tadashi?” Glancing over with his peripheral vision, he sees Hiro watching the dark scenery going by. There’s a small smile on his face, which makes Tadashi’s stomach roll in a pleasant manner.

“Takes one to know one, genius.” He pats his brother’s leg, before taking the next exit, and heads to the state beach.

They get there just as the last sliver of the sun goes down over the horizon. He had paid for a spot to camp at the last minute, and was pleased to find that it wasn’t that busy. Maybe Honey Lemon had been wrong? Or maybe the people would be coming later. It didn’t matter to him. He turns off the truck, then gets out, stretching his body before heading to the back. He sees Hiro standing next to him, and starts handing him stuff.

“Where are we setting up?” His brother asks, still looking put out for being pulled out on this adventure.

“Would you try to have a little fun, knucklehead?” He piles some more stuff into his arms, before grabbing the last of the gear. Locking up the truck, he starts to walk. “Follow me.”

He’s camped here so many times over the years that he knows the layout fairly well. They make their way towards the back of the camp area, which suits him just fine. If there’s a bigger turnout tonight, he’d rather stay away from the crowds. There aren’t any tents set up back here - a good sign that they should be alone tonight. He drops his stuff on the ground, and looks at his brother.

“So, you remember how to pitch a tent?” He asks, wiping his hands off on his thighs.

“What kind of tent do you mean?” His brother speaks under his breath, a smirk on his face.

Ignoring the comment, and ignoring how it makes the blood rush in his ears, he squats down, and starts to take the material out for the tent. “Make yourself useful, and help me assemble this, dummy.”

“Right.”

Once they get the four person tent set up, both roll out their sleeping bags. Grabbing the air mattress out of the bag, he pumps it up, then puts it down on the floor, the two of them situating their sleeping bags next to each other on top of the queen sized mattress. Hiro starts to move to crawl into the tent, but Tadashi grabs his shoulder to stop him. His hand burns slightly at the touch, not sure just what the heck is happening, but he brushes it aside, as he sees Hiro glaring up at him.

“We’re going on a hike.” He shakes his head. “Come on.”

“What about the tent??” Hiro asks. “Aren’t you worried that someone might steal our stuff?”

“Just how long has it been since you’ve been camping?” Tadashi doesn’t understand why Hiro is being so difficult right now. “It can’t be that long.”

“Let’s see…” His brother bounces on his heels. “I’m eighteen….so, um….8 years?”

“Really??” He feels awful, hearing that. “Is it when we went with Aunt Cass up to Yosemite?”

Hiro nods his head. “Yep. And if you remember, I did not have a lot of fun on that trip.” Images of Hiro accidentally moving through poison ivy flits through his brain, red blotchy skin looking awful for the few days they had been up there. “And _that’s_ why I hate camping.”

“Well, good news. There’s no poison ivy here.” He smiles, and sees his brother finally begin to relax. “Come on, don’t you want to go see the tide pools?”

“There are tide pools here??” That gets Hiro excited.

He smiles, and ruffles his brother’s hair. “Come on, knucklehead. Let’s go.” He puts his baseball cap on backwards, enjoying the look of shock he sees on Hiro’s face. “What?”

“N-Nothing.” Hiro looks away, but not before Tadashi can see the blush on his cheeks. That dip in his stomach returns, Tadashi pushing thoughts away that he has no business entertaining. “So, tide pools? With like, sea urchins and starfish, and stuff?”

“You got it.”

The two walk head towards the beach, the sounds of the surf becoming more pronounced the closer they get to the shoreline. He turns around, and sees the moon coming up over the cliff. He stops walking, and holds his arm out, forcing Hiro to stop.

“Dick, what do you think you’re doing?” His brother huffs.

“Look behind you, Hiro.” He points up to the sky.

Thankful that his brother actually listens to him, he feels a smile tug on his lips when he hears Hiro gasp, and then say ‘Wow’ under his breath. He stands behind him, pressing his chest to Hiro’s back, resting his elbows on top of Hiro’s shoulders, folding his hands on the top of his head to rest his chin there without hurting him. Hiro doesn’t move, and instead moves back a little, the lower halves of their bodies coming dangerously close together. Tadashi keeps his breath steady, but his heart is going a mile a minute.

“The moon is so big,” Hiro’s voice carries a hint of awe. “This is a supermoon?”

“It is. Do you know why it looks larger than it really is?” He asks, wondering if his brother has paid any attention in his astronomy class. He feels Hiro shake his head, strands of hair tickling his palms. “It’s the closest the moon is to our planet.”

“Wow….” Hiro leans his head back more, Tadashi’s hands falling off the top of his head. “It’s pretty awesome.”

Feeling his heart start to beat quicker, Tadashi takes a chance and speaks softly against his brother’s ear. “Would you like to see something else that’s awesome?”

He sees Hiro shiver, and knows it isn’t because there’s a chill in the air. No, it’s for another reason, and Tadashi’s stomach tumbles over and over at the realization. “S-Sure, ‘Dashi.” Hiro steps away from him, the two of them needing their distance for the moment. “The tide pools?”

“Follow me.” He turns on his heel, and starts to head back down towards the beach.

More people are showing up, and with good reason. Tadashi can see the natural phenomenon happening in the surf, even from this far away. “Hiro?” He stops walking, and looks at his brother, who’s looking up at him. “You trust me, right?”

“Yeah….? Why?” Hiro asks, looking up at him quizzically.

“Close your eyes, and give me your hand?” Tadashi asks. “Please?”

Without question, Hiro does as he’s asked him, holding out his hand for Tadashi to take. He does, a small thrill racing through him as their hands connect. He locks his fingers with Hiro’s, their palms resting comfortably together. As they get closer, Tadashi can see that the waves are glowing with the bioluminescent algae, just as Honey Lemon said it would be. He walks the two of them along the shore, moving towards an area where there aren’t a lot of people gathered, as there are quite a few of them now on the beach.

“‘Dashi, when can I open my eyes??” Hiro asks, whining.

Smiling, he waits for a wave begin to crest. “Okay, Hiro. Open your eyes.”

He has timed it just right. As Hiro opens his eyes, the wave starts to fall, the water becoming illuminated with the algae. He hears him gasp, the fingers against his squeezing his hand. Tadashi smiles, not saying a word, and instead keeps watching the wonderment on Hiro’s face make him look so _beautiful_. He’s so glad that he decided to take him down here.

“This is amazing,” Hiro whispers, after the fourth waves crashes towards the shore. “D-Did you know this was going to happen?”

Tadashi nods his head. “Yep. Honey Lemon was talking about it today, and I knew I had to bring you down here to see it with me.”

“Why not just go with her?” He hears a little resentment in his brother’s voice, which makes his stomach twist in knots. “Wouldn’t it be more romantic with a girl?”

“Hey.” He lets go of Hiro’s hand, and places it on his shoulder, turning him to look at him. “I’m here with you because I want to be here. Don’t think I’m settling for you, that you’re second best or something silly like that.” Without thinking, he places his hand on the side of Hiro’s face, his thumb stroking his cheek. “I asked you to come down here with me because I wanted to share this moment with _you_ , Hiro. No one else.”

The way Hiro’s eyes become half-lidded steals his breath away. “Do you mean that…?” His voice comes out in a soft whisper.

“Course, knucklehead.” He smiles, and pulls Hiro to be against his side. If he had kept his hand on his face, he would have been tempted to touch his brother’s lips, and that shouldn’t happen - not out here. “Let’s watch the ocean, hmm?”  
“Y-Yeah…”

After about an hour, the crowd starts to thin out, the algae still glowing bright under the water. Neither of them speak, and instead just enjoy being close to one another. After a while, Hiro stands in front of him, and he wraps his arms around his brother’s middle, holding him close to his body, Tadashi’s chest to Hiro’s back. When the water starts to dim a little, they decide to head back up to their tent. When they get there, Tadashi sees that no one has camped around them. He opens the tent flap, allowing Hiro to enter first, and then follows after him, zipping it up so that they’ll have some privacy.

“You ready to sleep?” He asks, toeing off his shoes before sliding into his sleeping bag.

Hiro gets in his sleeping bag, and shrugs his shoulders. “I’m not really tired. I’m actually kind of awake right now.”

“Oh?” He asks, turning on his side to look at him. The moon is bright enough that it illuminates their tent with soft light, making it easy to see Hiro. “Something on your mind?”

“Not really,” his brother speaks softly. “Hey, Tadashi? Can I ask you a question?”

“You just did.” He smirks, enjoying the glare that his brother throws his way.

“Ha ha.” Hiro rolls his eyes. “How about we unzip your sleeping bag, and lay it flat against the mattress, and then use mine as a blanket?”

That doesn’t sound like such a bad idea, except Tadashi isn’t sure he can trust himself to be that close to his brother. Not with all these weird feelings now going through his mind and body. But, the look on his brother’s face makes him push away all of those anxieties. “Sure, Hiro.” He gets out of his sleeping bag, and unzips it all the way. Hiro does the same to his own. Tadashi throws his opened up bag across the mattress, and then lays back down. “You gonna lay down with me, Hiro?” He asks, watching his brother stand next to the mattress with a strange look on his face.

“R-Right.” Hiro nods, and gets on the bed beside him, then arranges his sleeping bag over the two of them.

Knowing that it’s going to be a long night, he rests his hands on top of his chest. Looking up at the sky through the top of the tent, he can feel Hiro’s warmth so close to him, but so far away. After a few minutes, he feels Hiro begin to scoot closer to him, and he wonders if he should put his arm around him, or if he should just let him rest his head on his upper arm. He’ll decide what to do when Hiro makes his move - that is, if he does.

His heart is pounding hard in his chest, feeling restless when he knows he should be tired. He can feel the same waves coming off of his brother’s body. Deciding that not speaking wasn’t going to do either of them any favors, he decides to clear his throat, and feels Hiro jump slightly. “Hiro? Is something the matter?”

“No, ‘Dashi. I’m just a little warm.” Hiro speak softly.

“Do you not want to use the sleeping bag?” He turns over, and looks over at him. Chocolate colored eyes look bright, cheeks slightly flushed. “Hiro?”

“I’m sorry,” his brother whispers. “I’m not sure what’s wrong with me right now.”

Tadashi lifts his hand, and places it against his cheek, feeling the heat from his face transfer to his palm. Or is it the opposite? He’s not sure, but his eyes are focused on Hiro’s labored breathing. He moves his head closer, looking into his eyes. “What’s the matter?”

“I’m having strange thoughts right now,” Hiro admits.

“Tell me them?” He asks, stroking his cheek with his thumb, just like he had done back on the beach. “Do you want to go home?”

Hiro shakes his head. “No, I don’t. I…. I’m not sure how to say this.”

“Do you want to just whisper it into my ear?” He asks, his thumb traveling dangerously close to Hiro’s lips.

His brother turns his head, his thumb caressing his upper lip with the small movement. He hears himself gasp softly, as he looks into Hiro’s eyes, which are half-lidded, whatever he had felt back on the beach coming back full force. Hiro’s lips pucker, and place a soft kiss on the pad of his thumb, causing Tadashi to groan softly. Moving towards him, Hiro places his lips against his ear. “I want us to kiss, ‘Dashi. I want to be in your arms.”

Another soft groan leaves his throat, as Hiro turns his head, to look into his eyes. “Really?” Hiro nods his head slowly, as his lips gravitate towards his thumb, which has been frozen in the air since Hiro moved away from him. “If we do this…”

“I know, ‘Dashi.” Hiro looks into his eyes. “It’s just a kiss.”

He wants to tell him it’ll be much more than that, but he doesn’t want to frighten him. Hiro’s of age, and really - what’s the harm in a little kissing? Tadashi closes his eyes, and presses his forehead against Hiro’s. “Okay, Hiro.”

With a tilt of his head, he starts to leave soft kisses on his brother’s cheek, then hovers over his mouth. He can feel his body responding instantly, his arms circling around Hiro’s body, as he closes the gap between their mouths. His lips tingle with each soft touch of Hiro’s lips against his, as they both let go of the hesitancy, and start to kiss one another with more confident kisses. He feels Hiro’s arms wrap around his neck, and feels his lips part for him, allowing him to push his tongue into his mouth.

Hiro moans softly, Tadashi capturing it with his own mouth, as he starts to explore his mouth with his tongue. Each flick of the tip of his tongue earns another soft moan, and the grip that Hiro’s has on his shoulders tighten. He leads the kiss, but then takes a step back when he feels Hiro start to rub his tongue against his own, a low moan vibrating in his own throat. He presses closer to him, his leg between Hiro’s. His knee pushes upwards, and their kiss breaks off as Hiro leans his head back, emitting another soft moan.

“Aah…” Hiro moans, arching back more as Tadashi keeps pushing his knee upwards. “Oh, that feels good.”

Not wanting to stop kissing him, Tadashi starts to kiss his neck. “This is more than just a kiss, Hiro,” his voice comes out a little bit husky.

“Do you….mmm...wanna stop…?”

Lifting his head up, he looks into Hiro’s eyes. “If I say no? Will that sway what you want?”

“I want this, ‘Dashi. I’ve….I’ve been having these thoughts of you for a little bit now.” Hiro’s eyes seem to shine in the moonlight. “That’s why I didn’t want to come out here tonight.”

That news surprises him. “Really? I figured you didn’t want to come because you thought it was going to be boring.”

“No. I didn’t want to sleep close to you, because I didn’t want you to know about these dreams I keep having of you,” Hiro closes his eyes, a moan passing from his lips as Tadashi starts to grind his knee against his crotch again. “Nngh…”

Chuckling low, he rubs his nose against Hiro’s neck. “You know we share a room, right?” He kisses his lips softly.

“I know.”

He pulls his knee away, and moves to straddle his brother’s hips with his own. The mattress is holding firm, Tadashi thankful to Wasabi who had suggested he construct an air mattress of the same material that he used to make Baymax. He looks into his brother’s eyes, loving how his mouth parts, the soft pants of breath leaving his mouth a sign that what he’s doing to him is good. He lowers himself down, and starts to roll his hips slow, keeping his eyes on Hiro.

“How’s this feel, Hiro…?”

A leg hooks around his middle, pulling him down closer to him. “Mmm….Feels really nice, ‘Dashi…”

Their hips roll together, both of their clothed cocks rub against one another. The sound of the waves crashing surrounds them, as they both rock faster together. A part of him wants to pull Hiro out of his pants, and take his own cock out of his pants, but with the way they keep moving, it’s a lost cause. Hiro’s mouth latches onto his neck, muffling his moans as they grind against each other, whatever tension that’s been happening between the two of them suddenly dissipating with each thrust. Tadashi buries his face against Hiro’s neck, and bites down hard when he feels himself start to come, the warmth flooding his underwear, his body feeling impossibly warm. More wetness joins his, Hiro coming only a few moments after him with a loud, muted moan.

He kisses the small mark he’s left just below Hiro’s collar, glad he had been smart enough to leave it in an inconspicuous place. He can feel the hickie blooming on the side of his neck, but it doesn’t bother him. He lifts his head, and looks at Hiro, studying his features, as he comes down from their shared orgasm. When he’s satisfied by his breathing, he places his lips against his, and starts to kiss him softly.

They move, their kiss ending, as Hiro rests his head against his chest. “Thanks for making sure I came out here tonight, ‘Dashi. I know I was trying not to, but I’m really glad that I did.”

“I’m glad you came too.” He smirks, grunting when Hiro slaps his chest. He laughs, then kisses his forehead. “But really, there isn’t anyone else I’d rather see that with than you, Hiro.”

“I love you, Tadashi.”

“I love you too, Hiro.”

***

The next morning, they change into clean clothes, sharing kisses as they pack up their things. As they walk back to the car, they hear a familiar voice. Or rather, voices.

“Well, well, well! If it isn’t the Hamada bros!” Fred calls out. “Didn’t know the two of you were out here camping too!”

Honey Lemon walks behind him, a bright smile on her face. “Hiro! Tadashi! Did you guys get to see the algae?? Wasn’t it just so cool?”

“It was, Honey.” Tadashi grins. “I didn’t know you guys came out here too.”

A loud snap sounds to their left. “Like we’d miss this once in a lifetime opportunity.” Gogo says. “Hey, Hiro.”

“Hey guys.” Hiro smiles. “You guys wanna come back to the Lucky Cat, and have some breakfast?”

“I’ll drive!” Wasabi comes up behind them. “I’m the only one that got proper sleep last night.”

“Sounds good.” Tadashi nods. “See you guys back in the city?”

“You got it, Hamada-san,” Fred calls out, as the two Hamadas head back to the truck.

After getting all the stuff situated in the back, Tadashi gets into the cab, and sees Hiro looking out towards the ocean. “You okay, bud?” He asks, turning the truck on.

“Just thinking.”

“About what?” He asks, as they start to drive, heading towards the highway.

“Did you know they were going to be here?”

He shakes his head. “No, I didn’t. And you know what? I’m glad they got to see it, but I’m glad that we didn’t see them until this morning.”

“Why?”

“Because, I got to share that experience with only you.” He reaches over, and takes Hiro’s hand. “You’re the only one I wanted to be with last night.”

Hiro squeezes his hand. “I’m glad, ‘Dashi. That makes me really happy.”

“Good.”

They get to their place back in San Fransokyo, and see that the nerd squad has beaten them. How, Tadashi isn’t sure because he knows Wasabi drives carefully. He grabs their stuff, and drops it in the garage, before going into the cafe, where he sees Aunt Cass is already mauling his brother, the rest of the squad sitting at their normal table.

“You guys went and saw the glow in the dark stuff?” Aunt Cass asks, pulling him into the hug, as she hugs the both of them tightly. “How neat!”

“Yeah, Aunt Cass. It was really neat. One of the best nights of my life, that’s for sure.” Hiro says, his hand reaching down to touch Tadashi’s. He brushes his hand against his, sharing the same sentiments non-verbally.

“That’s awesome, little man! How about I rustle up some grub for everyone? I bet you’re all starving.”

“Famished, Miss Cass.” Fred calls out from across the room. “Please bring everything, and then another round.”

Hiro and Tadashi look at each other, and laugh. Yes, last night had definitely been one of the best nights of Tadashi’s life. He hopes that there will be many more like it, now that they’ve crossed the line, opening a limitless amount of possibilities.


End file.
